Coma and Persistent Vegetative State: An Exploration of Terms

By Cheryl Arenella MD, MPH

Many of us have heard through the media about the trials of Terri Schiavo and her family.  Terri Schiavo was an unfortunate young woman who suffered a cardiac arrest many years ago with subsequent brain damage from lack of oxygen.  She had been in a persistent vegetative state since then, and was maintained on tube feedings.  We heard about the disagreements between her family and her husband as to what Terri would want in this situation.  Unfortunately, her whole family has been torn apart by the conflict surrounding her husband’s decision, backed by the courts, to discontinue her tube feedings. 

Regardless of what opinions were expressed about the continuation or discontinuation of Terri Schiavo’s tube feedings, the emotions of those expressing their views ran high.  But emotions can sometimes lead us astray, especially if the facts of a situation are distorted, misrepresented or not understood.  Shedding light on areas that are poorly understood can only help inform our opinions and enable us to make more sound decisions for ourselves and those whose care has been entrusted to us.

To that end, let us explore some of the terms we heard during the debate surrounding the care of Terri Schiavo.  We will view a definition and description of “coma” as well as a “persistent vegetative state” (PVS), discuss the chances for recovery, and briefly look at the long term effects of these conditions.  We will explore the possible role of hospice programs in caring for persons with coma or a PVS.  The goal of the discussion is to provide a reasoned framework for making treatment decisions for persons suffering from coma or a PVS.  With the information provided, perhaps the burden felt by those in decision-making roles will be greatly lessened.

What is a coma?

Coma is a state in which the cortex or higher brain areas of a person are damaged resulting in loss of consciousness, inability to be roused, and unresponsiveness to pain, sound, touch and light.  If lower brain centers are damaged, a respirator may be required for the person to breathe.  The damage may be reversible or irreversible.

What causes a coma?

There are various causes of coma, including:

  • Stroke caused by bleeding or clots
  • Trauma to the brain
  • Masses or tumors in the brain
  • Metabolic imbalances such as high or low blood sugar, high blood calcium, or abnormalities stemming from liver or kidney failure
  • Lack of oxygen to the brain for prolonged periods of time, such as when a person suffers cardio-respiratory arrest (heartbeat and breathing stops)
  • Hypothermia, when the body’s temperature falls dangerously low
  • A post-seizure state
  • Toxic effects of drugs or alcohol

What is a Persistent Vegetative State (PVS)?

A vegetative state exists when a person is able to be awake, but is totally unaware.  A person in a vegetative state can no longer “think,” reason, relate meaningfully with his/her environment, recognize the presence of loved ones, or “feel” emotions or discomfort. The higher levels of the brain are no longer functional.  A vegetative state is called “persistent” if it lasts for more than four weeks.

What does a person in a PVS “look like”?

Like a person in a coma, a person in a PVS is bed or chair-bound, is totally dependent for all care needs, cannot eat or drink, cannot speak, and is incontinent of urine and bowels.         

Unlike a person in a coma, a person in a PVS has sleep-wake cycles or periods when he/she is awake and periods when he/she is asleep, can cough, sneeze, scratch and even cry or smile at times. The person may at times move his/her arms or legs. A person in a PVS may have automatic reactions to touch (drawing the body part away), sound (turning the head toward) and light (blinking the eyelids). The person’s eyes move and stop randomly.  If the person’s gaze happens to momentarily stop in the direction of someone at the bedside, that person might misinterpret this as “He/she is looking at me!” These behaviors can be disconcerting and confusing to an onlooker, especially a loved one, who may misinterpret them as an indication that the person in a PVS has awareness but is unable to communicate this to those around them.  However, all of these are automatic behaviors that do not require any functioning of the thinking part of the brain.

What causes a PVS?

Coma can progress to a PVS.  In fact, a person rarely remains in a coma for more than two to four weeks without recovering, dying, or progressing to a PVS.  End stage dementia can also progress to a PVS.

What are the rates of recovery from a coma and a PVS?

The recovery rate is very dependent upon the cause of the coma/PVS, whether the cause is reversible or not, the amount of damage to the brain, the region of the brain that is damaged, and the amount of time that the person is in a coma or a PVS.  When the cause of a coma is corrected before permanent brain damage occurs, the coma generally reverses within days.

However, when the death of large areas of the brain occurs, the outcome is generally grim.  Dead brain tissue does not regenerate.  Recovery from illnesses symptomatic of dead brain tissue (e.g. stroke) usually is a result of other brain tissue being trained to assume the functions of the lost tissue.  If not enough brain tissue is left to take over the functions of the lost brain tissue, recovery will not occur.  The longer the coma, the larger and more diffuse the area of damage, the older the person, the less are the chances of reversal of the coma and recovery of function.

Since a PVS is a late stage outcome of causes of irreversible coma, or the end stages of a dementia, the outlook for recovery is always poor for a person in this state. 

What about people who recover from a coma after months or even years?

Those cases actually are extremely rare.  If a coma is caused by traumatic injury with bleeding in the brain, and the injured area is limited, a person has a chance of recovering even when the coma has lasted for several months.  This is more common in younger patients.  But even in a young person suffering brain trauma, if the coma lasts more than six months, that person will rarely recover.

If a person suffers from a prolonged coma not due to trauma, for instance due to a stroke, the chance of recovery is bleak.  The rare person who is destined to recover will inevitably show some increase in responsiveness and functioning, however gradual, within the first days to weeks of becoming unconscious.  The lack of any improvement over time is another signal that recovery will not occur.

A person who suffers from a prolonged coma due to diffuse irreversible damage to the brain caused by a prolonged period of oxygen deprivation, usually more than four or five minutes, has the least chance of recovering.  If a coma from this condition, known as “anoxic encephalopathy,” lasts more than a week, recovery is extremely rare.  If death does not occur, a person with this condition will commonly progress to a PVS.

What happens to the body of the person in a prolonged coma or a PVS?

How many of us have seen a movie or television show where a person has been in an unresponsive coma for years, then suddenly wakes up one day, is fully alert, fully functional, and walks away with full strength, looking the same as the day he/she fell into the coma (except, perhaps, for the growth of a beard)?

The belief that an irreversible coma or a PVS is a stable non-progressive condition is inaccurate.  Although the brain lesion may not be changing or expanding, the changes occurring in the body are relentlessly progressive:

  • Muscles waste away, and limbs may become contracted and immoveable.
  • The person has a pre-disposition to develop recurrent pneumonia, due to immobility and an inability to keep secretions out of the lungs.  Lungs may scar and collapse over time.
  • The person has a predisposition to develop recurrent urinary tract infections, especially if a tube or Foley catheter has been inserted into the bladder to drain urine.  These infections not uncommonly become generalized, spreading to the bloodstream and causing sepsis, a life threatening infection of the blood.
  • Skin breakdown and ulcers occur commonly, since the person is unable to move and is incontinent, with no ability to control passage of urine or stool.  Once formed, these wounds are very difficult to heal on a permanent basis.

The longer the person is in a coma/PVS, the more profound and devastating are the changes suffered by his/her body. 

When a person is in a coma or a PVS, does the person suffer if feedings are discontinued, or not started?

A person in profound coma or suffering from a PVS is unable to experience hunger, thirst or pain.  Even if a pain stimulus occurs, there can be no recognition of its presence by the person unless the higher regions of the brain, the brain cortex, can receive and interpret the stimulus. In a person in deep coma or a PVS, the cortex does not function.  Therefore, this person would not suffer due to lack of artificial tube feedings.

Will hospice care for a person who is in a coma or in a PVS?

Hospices do care for persons with these conditions, although a patient like Terri Schiavo is unusual for a hospice.  When a person in a coma or a PVS is referred to a hospice, generally the person has decided a priori(e.g. through a living will) not to receive artificial nutrition or hydration should an irreversible coma or a PVS occur.  Or the family or other designated caregivers are in agreement that the person would not want these treatments.  Or the person is noticeably deteriorating in spite of artificial nutrition and hydration.  Death usually occurs well within six months of admission to the hospice.

What kind of care would a hospice provide for a person in a coma or in a PVS?

A hospice will provide similar care to a person in a coma or a PVS that would be provided to a conscious patient who cannot swallow or move well.          

When a hospice cares for a conscious person who is unable to swallow, the hospice will take care to prevent symptoms of thirst by moistening the mouth frequently.  The hospice will attempt to prevent skin breakdown by turning the person frequently and moisturizing and massaging the skin carefully.  If any signs of discomfort occur, medications are administered to maintain comfort.  These include medicines to treat pain, shortness of breath, lung congestion, fever, or any other problematic symptoms.  Since a person who is severely ill rarely feels hungry even when he/she does not eat, tube feedings are seldom used in a hospice. We know the approaches used by hospice work to keep the patient comfortable because patients who are still alert and able to communicate have told us these approaches keep them comfortable.

The same treatments and approaches used in a conscious patient to maintain comfort are used for the person who is in a coma or a PVS. Even though we do not believe he/she is capable of experiencing suffering or pain, all potential causes of discomfort are addressed.

In addition, the hospice provides emotional, social and spiritual care to the person’s family and loved ones during this traumatic time.  This family care extends beyond the one-year anniversary of the person’s death.

Making decisions about starting or stopping artificial nutrition and hydration, or using or foregoing other medical interventions for a person in a coma or a PVS is never easy.  Each person deserves to have the information necessary to make an informed choice for him or herself, or for a loved one.  Being informed involves knowing the immediate and long term effects of the disease on the person.  It is equally important to understand what the available treatments can and cannot do.  In this way, the benefits and burdens of each intervention can be weighed more effectively against the benchmarks of each person’s goals and beliefs.  More reasoned and consistent treatment decisions can then be made, which lessens the emotional burdens associated with the decision-making.  

About the author: Dr. Cheryl Arenelladoes health care consulting for programs focused on improving end-of-life care.  She has over 20 years of experience in the field of Hospice and Palliative Medicine.  She is a former trustee of the American Board of Hospice and Palliative Medicine and served for many years as a Medical Director for a large Medicare certified hospice, where she provided medical oversight, direct patient care and administrative program support.